Making the computer user friendly enabled it to be marketed to the masses. This involved a number of developments over the 70s and 80s, trickling in one at a time and each contributing to greater usability and marketability to a mainstream audience. These variously included the invention of the CRT, and then color, so that people didn't have to rel on a single line of output. Following this was such developments as the GUI, the graphical user interface, allowing for more intuitive computer use, and the mouse, allowing you to have something on the screen to point and click. Many of these are remarkably simple concepts to use in retrospect, but were huge leaps of invention at the time. Such things allowed computers to be usable to the geneal public.
Making them desirable, on the other hand, was a different trick. Though much cheaper than they had been, they were still quite expensive for most people. An ever-expanding number of software programs made them tempting, games, word processors, tools that took advantage of ever-increasing hardware improvement.
With the rise of the Internet, owning your own personal home computer became not just a desirable object to own, but a necessity to see the outside world. They became tools essentially for everyday life, from checking the news to keeping in touch with friends to playing games to even applying to jobs. They were a terminal by which anyone who could afford them accessed the world outside their immediate surrounding, and as such, has been deemed necessary for a complete life in the digital age.